Nerve cell suicide

The embryo produces many more neurones than it needs to ensure that all possible connections can be established and there will never be too few. The neurones that get to the right place and successfully make connections survive. Once an area of the brain has enough connections, any others growing towards the same point will die by switching on a 'cell suicide program' - apoptosis.

Only those neurones that make the right connections survive - the rest will die through apoptosis.